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into important crop plants, such as soybeans. Genetic engineering has also been used to protect plants from virus infection; expressing the coat protein gene of a virus, interfering with the uncoating of viral particles, and thus interrupting the virus replication cycle. Insect resistance has also been genetically introduced in plants.

Text 5.

Nanotechnology – a miracle of 21-st century?

The term 'nanotechnology' encompasses a huge range of activities. 'Nano' is used in the world of science to mean one billionth. E.g. a nanometer is a billionth of a metre. A nanometer is only ten atoms across! So generally nanotechnology is used to mean technology at the nanometer level. Nanotechnology attempts to achieve something useful through the manipulation of matter at this level.

To put it more formally, you can use the following definition: "Nanotechnologies are the design, characterization, production and application of structures, devices and systems by controlling shape and size at nanometer scale." At such scales, the ordinary rules of physics and chemistry no longer apply. For instance, materials' characteristics, such as their colour, strength, conductivity and reactivity, can differ substantially between the nanoscale and the macro. Carbon 'nanotubes' are 100 times stronger than steel but six times lighter.

History. Physicist Richard Feynman gave a lecture to the American Physical Society in 1959 which foresaw advantages from manufacturing on a very small scale - e.g. in integrated circuits for computers, for sequencing genes by reading DNA molecules and using machines to make other machines with increasing precision. However, the term 'nanotechnology' was first used by Norio Taniguchi in 1974, in a talk about how the accuracy of manufacturing had improved over time. He referred to 'nanotechnology' as that which achieved greater dimensional accuracy than lOOnm.

Feynman also envisaged machines that could pick up and place individual atoms. This development of this idea was later assisted by the invention of the scanning probe electron microscope (SPM) which allowed scientists to'see'and manipulate the individual atoms in a surface. In 1989 one of the defining moments in nanotechnology occurred when Don Eigler used a SPM to spell out the letters IBM in xenon atoms. For the first time scientists could put atoms exactly where they wanted them.

Molecular building blocks - Another great leap forward occurred in the shape of a new form of carbon. Harry Kroto from the University of Sussex, together with Richard Smalley and Robert Curl, discovered the carbon 60 molecule, which is shaped like a soccer ball. They named the molecular structure after the similarly shaped geodesic dome structure pioneered by the architect Buckminster Fuller. Unfortunately 'Buckminsterfullerene' is too long a name for most people and so they are often called 'Buckyballs'!

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There are two fundamentally different approaches to nanotechnology, termed 'top down' and 'bottom up'. 'Top-down' nanotechnology features the use of microand nano-lithography and etching. Here, small features are made by starting with larger

materials (e.g. semi-conductors) and patterning and "carving down" to make nanoscale structures io precise patterns. Complex structures including microprocessors containing hundreds of millions of precisely positioned nanostructures can be fabricated. Of all forms of nanotechnology, this is the most well established.

'Bottom-up', or molecular nanotechnology (MNT), applies to building organic and inorganic structures atom-by-atom, or molecule-by-molecule. Here we are using the forces of nature to assemble nanostructures - the term "self assembly" is often used. The self assembling properties of biological systems, such as DNA molecules, can be used to control the organization of species such as carbon nanotubes, which may ultimately lead to the ability to 'grow' parts of an integrated circuit, rather than having to rely upon expensive 'top-down' techniques. Nanotechnologies are widely seen as having huge potential in areas as diverse as healthcare, IT and energy storage. Governments and businesses across the world have started to invest substantially in their development. However there are also concerns regarding the safety of nanotechnology. These range from the more fanciful (such as Eric Drexler's imagined scenario of a world reduced to "grey goo", caused by self-replicating nano-robots) to the more realistic (such as the possible dangers of foreign nano-particles entering human organs and the bloodstream).

SOME SHORT-TERM NANO USES: Medical diagnostic tools and sensors. Solar energy collection (photovoltaics). Direct hydrogen production. Flexible display technologies and e-paper. Composites containing nanotubes. Glues, paints and lubricants. New forms of computer memory. Printable electronic circuits. Various optical components.

SOME LONGER-TERM NANO USES: Miniaturised data storage systems with capacities comparable to whole libraries' stocks. PCs with the power of today's computer centres. Chips that contain movies with more than 1,000 hours of playing time. Replacements for human tissues and organs. Cheap hydrogen storage possibilities for a regenerative energy economy. Lightweight plastic windows with hard transparent protective layers.

Ever since John Dalton convinced the world of the existence of atoms in 1803, scientists have wanted to do things with them. Nanotechnology takes that ability on to a new plane and opens up all kinds of futuristic imaginings. Essentially, nanotech is manipulation at the molecular scale - distances that may cover just a few millionths of a millimetre. But its potential is not just about being able to miniaturise things. Indeed, scientists and engineers recognise that there are fundamental limits to pure miniaturisation. Working at a scale a million times smaller than a pinhead allows researchers to "tune" material properties, making them behave in different ways to normal, largescale solids. This behaviour can be exploited in quite ground-breaking ways.

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Nature has been doing nanotechnology for a long time, and it has become expert in it. Consider the super-fine hairs on a gecko's feet which allow it to stick to walls and even hang upside down on a glass sheet. Learning from nature, nanotechnology promises humans ways of making systems that are smaller, lighter, stronger, more efficient, but cheaper to produce. "Nanotechnology is not a technology in its own right," explained Professor Mark Welland, head of the University of Cambridge Nanoscale Science Laboratory. "It is an enabling technology, so it will appear in many different products. It is already appearing in flash memory, computer chips, and it will increasingly be an enabling technology in other products like coatings, new types of sensors, especially in the medical area."

It is expected to transform the performance of materials, like polymers, electronics, paints, batteries, sensors, fuel cells, solar cells, coatings, computers and display systems. In five years'time, batteries that only last three days will be laughable, said Professor Welland. Similarly, in 10 years' time, the way medical testing is done now will be considered crude. To say that in five years, an iPod will have 10 times its current storage capacity will be conservative, he said. In the not-so-distant future, a terabit of data - equivalent to 10 hours of fine quality uncompressed video - will be stored on an area the size of a postage stamp. Clearly, the devices themselves will not be nano-sized. But nanotechnology will play its part in shrinking components! and making them work together a lot more efficiently. Although nano-devices can be built atom by atom, it is not realistic as a manufacturing option because it is slow and expensive, thinks Professor John Ryan, head of the Bionanotechnology Centre at Oxford University. "One of the major scientific challenges in the years ahead is to understand the fundamental biological principles and apply them to produce new types of nanotechnology," he said. "Armed with these design rules it may then be possible to make new types of nanodevice using materials that are more robust than bio-materials."

The Royal Society and the Royal Academy of Engineering has looked at current and future developments in nanotechnology and has reported on whether it will require new controls. It is hoped that the report grounds some unrealistic scenarios, while recognising that real concerns need to be addressed with regulation. "The one fantastical idea that has dogged nartotechnology is the self-replicating machine, the 'grey goo', scenario," said Professor Welland. "That is simply too far off. The complexity of designing a molecular machine is bad enough, but if you try to imbue that with self-replication, you could not even put a toe in the water to design it." The scenario sees swarms of self-replicating robots, smaller than viruses, multiplying uncontrollably and devouring Earth. Eric Drexler, who many consider to be a "father of nanotechnology", has distanced himself from the idea, saying such selfreplicating nanomachines are unlikely to be widespread. Similarly, fears over "green goo", the concern that self-replicating, nano-sized biological particles will move into human bodies and do unpredictable things, is scaremongering, thinks Professor Welland.

Professor Ryan agrees: “These science fiction scenarios have not only diverted attention away from the real advantages of nanotechnology, but also from issues

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that do raise concern”. Inhaled nanoparticles found in the bloodstream which have dispersed throughout the brain is a concern, he says. Whether this poses a health risk is not known. "If you look around at the moment in a big city, a significant proportion of material that you breathe in is already particulates - and a proportion of that is nano-sized, like diesel emissions," said Professor Welland.

Nano-materials exploit unusual electrical, optical and other properties because of the very precise way in which their atoms are arranged. This means fabrics could change colour electronically. Exposing an army uniform to ultra-violet light could activate changes without undressing. But it is in medicine that nanotechnology offers the most remarkable advances, according to Professor Ryan. "Nanomedicine will provide earlier and better diagnostics and treatment will combine earlier and more precisely targeted drug delivery," he said. The possibility of individualised therapy is also on the horizon. Nanotechnology in the form of flexible films containing miniaturised electrodes is expected to improve the performance of retinal, cochlear and neural implants. And it could lead to the miniaturisation of medical diagnostic and sensing tools which could drive down costs of such kits for developing countries. In this respect, nanotechnology could enable developing nations to leapfrog older technologies, in the way that copper wire and optical fibre telephony were superseded by mobile phones.

Industrial giants like GE are heavily involved in developing nanotechnology, 'We think that the biggest breakthroughs in nanotechnology are going to be in the new materials that are developed," said Troy Kirkpatrick at GE Global Research. These include corrosion-resistant coatings to make hydro-electric turbines more efficient in heavily-silted waters, and nanomembrane water filters to make for faster filtration. GE is also studying the properties of nano-ceramics, which can offer extreme strength, while still being lightweight. Because of the molecular structure of such materials, nano-ceramic coatings on aircraft could make them 10% more efficient, so less energy is used, producing fewer emissions.

GE Global Research is also looking to the electronics industry. "If you look at the chip makers of the world, the challenge they have is not to figure out how tb make them faster. The problem is they run so fast* the chips generate too much heat and melt. They need better materials for heat management," said Mr Kirkpatrick. Using materials which exploit properties of nanoparticles, GE has developed chip adhesives that can transfer heat out of the processor system more efficiently. "It is a start, and it is to show nanotechnology is finding its way into production and is changing the way we are doing science," said Mr Kirkpatrick.

Whatever nanotechnology does for the future, it will be an evolutionary process. One certainty is that there remains a plethora of uncertainties in the emerging field of nanotechnology. “Medical sensing is very attractive to everybody, but there could be a downside," explained Professor Welland. “If medical sensors become ubiquitous, our physical state could be monitored 24 hours a day, and if someone hacked into that data, there could be concerns”. “Which is indeed why regulation has to be addressed, but must not stifle nanotechnology's potential. One of the important things for me is that it ultimately means the most efficient use of materials and processes, which means it does not have to benefit just the G8

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nations” argued Professor Welland. "These sorts of materials, if they are able to do their job using less energy, should be available to everybody."

Text 6.

Food supplements in the USA

In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act of 1994[10] (DSHEA) as a product that is intended to supplement the diet and contains any of the following dietary ingredients: a vitamin, a mineral, a herb or other botanical (excluding tobacco), an amino acid a concentrate, metabolite, constituent, extract, or combination of any of the above.

Furthermore, it must also conform to the following criteria: intended for ingestion in pill, capsule, tablet, powder or liquid form not represented for use as a conventional food or as the sole item of a meal or dietlabeled as a "dietary supplement".

The hormones DHEA (a steroid), pregnenolone (also a steroid) and the pineal hormone melatonin are marketed as dietary supplements in the US.

Regulation

The Food and Drug Administration (FDA) regulates dietary supplements as a category of foods, and not as drugs. While pharmaceutical companies are required to obtain FDA approval which involves assessing the risks and benefits prior to their entry into the market, dietary supplements do not need to be pre-approved by FDA before they can enter the market. Instead, manufacturers and distributors who wish to market dietary supplements that contain a "new dietary ingredient" (defined as "a vitamin; a mineral; a herb or other botanical; an amino acid; a dietary substance for use by man to supplement the diet by increasing total dietary intake; or a concentrate, metabolite, constituent, extract, or combination of any of the above dietary ingredients" not marketed before October 15, 1994) must notify the FDA beforehand. The notification requires information indicating the ingredient is safe, and the ingredient can not be marketed (sold or delivered for sale) for seventy-five days following filing the information. During this time the agency reviews the information for adequacy and safety concerns; fifteen days after the this period (ninety days after the information was filed) the FDA posts nonproprietary information on their website. Listing the information means the ingredient can be marketed, but does not mean it is necessarily safe. [14] On September 24, 2007 the FDA has implemented a "current good manufacturing practices" policy to ensure dietary supplements "are produced in a quality manner, do not contain contaminants or impurities, and are accurately labeled" and covers the manufacturing, packaging, labelling and storing of supplements, with requirements for quality control, design and construction of manufacturing plants, testing of ingredients and final products, record keeping and complaints processes.

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The DSHEA, passed in 1994, was the subject of lobbying efforts by the manufacturers of dietary supplements and restricted the ability of the FDA to exert authority over supplements so long as manufacturers made no claims about their products treating, preventing or curing diseases. According to Consumer Reports, "The law has left consumers without the protections surrounding the manufacture and marketing of over-the-counter or prescription medications" and it became the FDA's responsibility to prove that a supplement wasn't safe. While pharmaceutical manufacturers must demonstrate their products are effective as well as being safe, supplement manufacturers are not required to demonstrate efficacy. The FDA has only ever found one dietary supplement to be unsafe, the weight loss/energy supplement ephedra. Discussing the legislation, Time referred to the DSHEA as "illconceived and reprehensible", that "gives the industry virtually free reign [sic] to market products defined as dietary supplements, while severely limiting the FDA's ability to regulate them".The DSHEA was heavily lobbied for by the supplement industry, and was criticized for exposing the public to worthless compounds that bilked consumers out of money to no benefit. Because of the requirements put into place by the DSFIEA, the FDA must demonstrate that individual supplements are unsafe using their adverse events reporting system, which it is estimated captures only 1% of all adverse events linked to supplements, [citation needed] The FDA has also lacked the funding to undertake the rigorous tests to meet the standards for a supplement to be considered "hazardous" and thus removed from the market; in the one situation where this standard was reached (ephedra), the agency faced significant opposition from the supplement industry and the United States Congress, instead limiting themselves to making announcements about problematic supplement safety records on their website.

A 2001 study, published in Archives of Internal Medicine, found broad public support for greater governmental regulation of dietary supplements than was currently permitted by DSHEA. The researchers found that a majority of Americans supported pre-marketing approval by the FDA, increased oversight of harmful supplements, and greater scrutiny of the truthfulness of supplement label claims.

Text 7.

Food additives

Food additives can be divided into several groups, although there is some overlap between them.

Acids

Food acids are added to make flavors "sharper", and also act as preservatives and antioxidants. Common food acids include vinegar, citric acid, tartaric acid, malic acid, fumaric acid, and lactic acid.

Acidity regulators

Acidity regulators are used to change or otherwise control the acidity and alkalinity of foods.

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Anticaking agents

Anticaking agents keep powders such as milk powder from caking or sticking. Antifoaming agents

Antifoaming agents reduce or prevent foaming in foods. Antioxidants

Antioxidants such as vitamin C act as preservatives by inhibiting the effects of oxygen on food, and can be beneficial to health.

Bulking agents

Bulking agents such as starch are additives that increase the bulk of a food without affecting its nutritional value.

Food coloring

Colorings are added to food to replace colors lost during preparation, or to make food look more attractive.

Color retention agents

In contrast to colorings, color retention agents are used to preserve a food's existing color.

Emulsifiers

Emulsifiers allow water and oils to remain mixed together in an emulsion, as in mayonnaise, ice cream, and homogenized milk.

Flavors

Flavors are additives that give food a particular taste or smell, and may be derived from natural ingredients or created artificially.

Flavor enhancers

Flavor enhancers enhance a food's existing flavors. They may be extracted from natural sources (through distillation, solvent extraction, maceration, among other methods) or created artificially.

Flour treatment agents

Flour treatment agents are added to flour to improve its color or its use in baking. Glazing agents

Glazing agents provide a shiny appearance or protective coating to foods. Humectants

Humectants prevent foods from drying out. Tracer gas

Tracer gas allows for package integrity testing to prevent foods from being exposed to atmosphere, thus guaranteeing shelf life.

Preservatives

Preservatives prevent or inhibit spoilage of food due to fungi, bacteria and other microorganisms.

Stabilizers

Stabilizers, thickeners and gelling agents, like agar or pectin (used in jam for example) give foods a firmer texture. While they are not true emulsifiers, they help to stabilize emulsions.

Sweeteners

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Sweeteners are added to foods for flavoring. Sweeteners other than sugar are added to keep the food energy (calories) low, or because they have beneficial effects for diabetes mellitus and tooth decay and diarrhea.

Thickeners

Thickeners are substances which, when added to the mixture, increase its viscosity without substantially modifying its other properties.

Safety

With the increasing use of processed foods since the 19th century, there has been a great increase in the use of food additives of varying levels of safety. This has led to legislation in many countries regulating their use. For example, boric acid was widely used as a food preservative from the 1870s to the 1920s, but was banned after World War I due to its toxicity, as demonstrated in animal and human studies. During World War II the urgent need for cheap, available food preservatives led to it being used again, but it was finally banned in the 1950s. Such cases led to a general mistrust of food additives, and an application of the precautionary principle led to the conclusion that only additives that are known to be safe should be used in foods. In the USA, this led to the adoption of the Delaney clause, an amendment to the Federal Food, Drug, and Cosmetic Act of 1938, stating that no carcinogenic substances may be used as food additives. However, after the banning of cyclamates in the USA and Britain in 1969, saccharin, the only remaining legal artificial sweetener at the time, was found to cause cancer in rats. Widespread public outcry in the USA, partly communicated to Congress by postage-paid postcards supplied in the packaging of sweetened soft drinks, led to the retention of saccharin despite its violation of the Delaney clause.

In September 2007, research financed by Britain's Food Standards Agency and published online by the British medical journal The Lancet, presented evidence that a mix of additives commonly found in children's foods increases the mean level of hyperactivity. The team of researchers concluded that "the finding lends strong support for the case that food additives exacerbate hyperactive behaviors (inattention, impulsivity and overactivity) at least into middle childhood." That study examined the effect of artificial colors and a sodium benzoate preservative, and found both to be problematic for some children. Further studies are needed to find out whether there are other additives that could have a similar effect, and it is unclear whether some disturbances can also occur in mood and concentration in some adults. In the February 2008 issue of its publication, AAP Grand Rounds, the American Academy of Pediatrics concluded that a low-additive diet is a valid intervention for children with ADHD:

"Although quite complicated, this was a carefully conducted study in which the investigators went to great lengths to eliminate bias and to rigorously measure outcomes. The results are hard to follow and somewhat inconsistent. For many of the assessments there were small but statistically significant differences of measured behaviors in children who consumed the food additives compared with those who did not. In each case increased hyperactive behaviors were associated

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with consuming the additives. For those comparisons in which no statistically significant differences were found, there was a trend for more hyperactive behaviors associated with the food additive drink in virtually every assessment. Thus, the overall findings of the study are clear and require that even we skeptics, who have long doubted parental claims of the effects of various foods on the behavior of their children, admit we might have been wrong."

In 2007, Food Standards Australia New Zealand published an official shoppers' guidance with which the concerns of food additives and their labeling are mediated.

There has been significant controversy associated with the risks and benefits of food additives. Some artificial food additives have been linked with cancer, digestive problems, neurological conditions, ADHD, heart disease or obesity. Natural additives may be similarly harmful or be the cause of allergic reactions in certain individuals. For example, safrole was used to flavor root beer until it was shown to be carcinogenic. Due to the application of the Delaney clause, it may not be added to fo Red 3, and Yellow 6 are among the food colorings that have been linked to various health risks. Blue 1 is used to color candy, soft drinks, and pastries and there has been some evidence that it may cause cancer. Blue 2 can be found in pet food, soft drinks, and pastries, and has shown to cause brain tumors in mice. Red 3, mainly used in cherries for cocktails has been correlated with thyroid tumors in rats and humans as well. Yellow 6, used in sausages, gelatin, and candy can lead to the attribution of gland and kidney tumors and contains carcinogens, but in minimal amounts.

Text 8.

Food preservation

Preservation processes include:

Heating to kill or denature micro-organisms (e.g. boiling). Oxidation (e.g. use of sulfur dioxide).

Toxic inhibition (e.g. smoking, use of carbon dioxide, vinegar, alcohol etc.). Dehydration (drying).

Osmotic inhibition (e.g. use of syrups).

Low temperature inactivation (e.g. freezing).

Ultra high water pressure (e.g. fresherized, a kind of "cold" pasteurization, the pressure kills naturally occurring pathogens, which cause food deterioration and affect food safety).

Combinations of these methods.

Drying

Main article: Drying (food).

One of the oldest methods of food preservation is by drying, which reduces water activity sufficiently to prevent or delay bacterial growth.

Refrigeration

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Refrigeration preserves food by slowing down the growth and reproduction of microorganisms and the action of enzymes which cause food to rot. The introduction of commercial and domestic refrigerators drastically improved the diets of many in the Western world by allowing foods such as fresh fruit, salads and dairy products to be stored safely for longer periods, particularly during warm weather.

Main article: Frozen food

Freezing is also one of the most commonly used processes commercially and domestically for preserving a very wide range of food including prepared food stuffs which would not have required freezing in their unprepared state. For example, potato waffles are stored in the freezer, but potatoes themselves require only a cool dark place to ensure many months' storage. Cold stores provide large volume, longterm storage for strategic food stocks held in case of national emergency in many countries.

Heat treating

Main articles: Thermization, Pasteurization, and Sterilization (microbiology). This section requires expansion.

Vacuum packing

Vacuum-packing stores food in a vacuum environment, usually in an air-tight bag or bottle. The vacuum environment strips bacteria of oxygen needed for survival, slowing spoiling. Vacuum-packing is commonly used for storing nuts to reduce loss of flavor from oxidation.

Salt

Salting or curing draws moisture from the meat through a process of osmosis. Meat is cured with salt or sugar, or a combination of the two. Nitrates and nitrites are also often used to cure meat and contribute the characteristic pink color, as well as inhibition of Clostridium botulinum.

Sugar

Sugar is used to preserve fruits, either in syrup with fruit such as apples, pears, peaches, apricots, plums or in crystallized form where the preserved material is cooked in sugar to the point of crystallisation and the resultant product is then stored dry. This method is used for the skins of citrus fruit (candied peel), angelica and ginger. A modification of this process produces glacй fruit such as glacй cherries where the fruit is preserved in sugar but is then extracted from the syrup and sold, the preservation being maintained by the sugar content of the fruit and the superficial coating of syrup. The use of sugar is often combined with alcohol for preservation of luxury products such as fruit in brandy or other spirits. These should not be confused with fruit flavored spirits such as cherry brandy or Sloe gin.

Artificial food additives

Preservative food additives can be antimicrobial; which inhibit the growth of bacteria or fungi, including mold, or antioxidant; such as oxygen absorbers, which inhibit the oxidation of food constituents.